Use of Single-factor Authentication

The use of single-factor authentication can lead to unnecessary risk of compromise when compared with the benefits of a dual-factor authentication scheme.


While the use of multiple authentication schemes is simply piling on more complexity on top of authentication, it is inestimably valuable to have such measures of redundancy. The use of weak, reused, and common passwords is rampant on the internet. Without the added protection of multiple authentication schemes, a single mistake can result in the compromise of an account. For this reason, if multiple schemes are possible and also easy to use, they should be implemented and required.


The following examples help to illustrate the nature of this weakness and describe methods or techniques which can be used to mitigate the risk.

Note that the examples here are by no means exhaustive and any given weakness may have many subtle varieties, each of which may require different detection methods or runtime controls.

Example One

In both of these examples, a user is logged in if their given password matches a stored password:

unsigned char *check_passwd(char *plaintext) {
  ctext = simple_digest("sha1",plaintext,strlen(plaintext), ... );
  //Login if hash matches stored hash
  if (equal(ctext, secret_password())) {
String plainText = new String(plainTextIn);
MessageDigest encer = MessageDigest.getInstance("SHA");
byte[] digest = password.digest();
//Login if hash matches stored hash
if (equal(digest,secret_password())) {

This code fails to incorporate more than one method of authentication. If an attacker can steal or guess a user's password, they are given full access to their account. Note this code also exhibits CWE-328 (Reversible One-Way Hash) and CWE-759 (Use of a One-Way Hash without a Salt).

See Also

Authentication Errors

Weaknesses in this category are related to authentication components of a system. Frequently these deal with the ability to verify that an entity is indeed who it clai...

OWASP Top Ten 2017 Category A2 - Broken Authentication

Weaknesses in this category are related to the A2 category in the OWASP Top Ten 2017.

Authenticate Actors

Weaknesses in this category are related to the design and architecture of authentication components of the system. Frequently these deal with verifying the entity is i...

Comprehensive CWE Dictionary

This view (slice) covers all the elements in CWE.

Weaknesses without Software Fault Patterns

CWE identifiers in this view are weaknesses that do not have associated Software Fault Patterns (SFPs), as covered by the CWE-888 view. As such, they represent gaps in...

CWE Cross-section

This view contains a selection of weaknesses that represent the variety of weaknesses that are captured in CWE, at a level of abstraction that is likely to be useful t...

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